Automatic blowdown for steam separator



May 24, 1960 J. E. LA ROCQUE ET AL 2,937,845

AUTOMATIC BLowDowN FOR STEAM sEPARAToR Filed Nov. 22, 1954 ssheets-sheet 1 Si 'lumi 'JOSEPH E. LA 90cm/E FLY/94 CHAQLES E. IMPEY May24, 1960 J. E. LA RCQUE ET AL AUTOMATIC BLowDowN FOR STEAM sEPARAToR 3Sheets-Sheet 2 Filed Nov. 22, 1954 ITZEHZDEE dose/DH E. LA Roem/E ,fl zM f im,

.0 9 3 Q M) w @XM o NJN// 7 Vo .M5 4 4 4 E 7 May 24, 1960 J. E. LAROCQUE ETAL AUTOMATIC BLOWDOWN FOR STEAM SEPARATOR 3 Sheets-Sheet 3Filed Nov. 22, 1954 JEZEHZDEE I JOSEPH E. LA QocQuE CHARLES E. /NPEY hUnited States, Patent AUTOMATIC BLOWDOWN FOR STEAM SEPARATOR `loseph E.La Rocque, Chicago, and Charles E. Impey, Lombard, Ill., assignors toVapor Heating Corporation, Chicago, Ill., a corporation of DelawareFiled Nov. 22, 1954, Ser. No. 470,182

1 Claim. (Cl. 251-14) The present invention relates to automaticYblowdown control mechanism for steam separators associated with steamgenerators of the water-tube coil type such as are usually employed tosupply steam to the heating lsystems of diesel powered passenger trains.The invention 'is however capable of a wide variety of other uses andthe same may readily be employed, with or without modication, forstationary installations wherein a plurality of steam generators areused for supplying steam and it is desirable to blow down their steamseparators from a remote location at predetermined intervals. Theinvention, for illustrative purposes, is herein shown and described inconnection with diesel powered passenger trains wherein it hasparticular advantages that will appear presently.

Diesel locomotive installations usually employ one or more steamgenerators to supply steam to the heating equipment of the locomotiveand the trainof passenger cars connected thereto. Steam separator unitsassociated with such generators receive a mixture of steam and hot waterfrom the generator coils near the top of the unit and yoperate upon thegravity principle to separate the steam from the water. The mineralconstituents in the water are coagulated by the reaction of heat andwater treatment chemical introduced therein and these minerals, in theform of sludge, are carried by the water into the separator. The waterand mineral sludge drop to the bottom of the separator while the steamis conducted 'from the top of the separator unit to the various heatexchange devices vwhich may be employed in the heating system. Toprevent undue accumulation of such sludge in the separator unit ablowdown vvalve is provided at the bottom of the unit whereby the sludgeaccumulation may periodically be ejected from the separator to theatmosphere.

Heretofore, Where manual blowdown operations were resorted to,infrequent and irregular blowdowns resulted in undue waste of water aswell as frequent clogging of the separators. In passenger traininstallations involving two or more locomotives, or dual locomotiveunits, eiective blowdown operations necessitated the services of atrainman, usually a reman, and required himito leave his station in thelocomotive cab and walk through the various articulated units of thelocomotive to effect the necessary blowdown operations of the-steamseparator associated with the steam generator in such units. Inrailroads encountering bad water conditions, high water consumption andfrequent clogging of the steam separators have become factors thatmaterially add to the cost of maintenance.

The present invention is designed to overcome the above notedlimitations that are attendant upon manual blowdown operations invpassenger train operation and, toward this end, it contemplates theprovision of a separator blowdown control mechanism which will operateautomatically to blow down the steam separator of a steam generator, orto simultaneously blow down the separator unitsof all steam generatorsemployed in any particular train installation, at frequent predeterminedintervals with each blowdown operation lasting a predeterf mined periodof time.

In carrying out these aims, brieliy, the invention contemplatesthe-provision of an electrically operated control valve, one of whichmay be employed for operating an air cylinder associated with eachblowdown valve'of a steam separator, together with a compact unitaryassemblage of electrical control mechanism, kcapable of 'being installedwithin a control boit or on a control panel ata location remote from`the steam generating plant, which mechanism is timer controlled so thatautomatic blowdown operations will take place according to apredetermined time schedule. The control mechanism further .includes amain switch by means of which the apparatus may be set for automaticoperation or disabled at will and also includes push button meanswhereby, if desired, manual control of blowdown operations may beeffected so as to completely purge all separators of collected sludgebefore the train enters a station and immediately after the train leavesthe station.

The provision of a blowdown control apparatus of the character brieflyoutlined above being among the Yprin- .cipal objects of the invention,other objects and advantages will appear as the following descriptionensues.

control mechanism showingthe same partly in perspec.-

tive` and partly in section as being applied to a blowdown valveassociated with a steam separator. v Fig. 3 is' an elevational viewV ofa steam generator having a steam separator associated therewith andshowing the control mechanism of the presentrinvention applied thereto.v Fig. 4 is a plan view of a control panel on which certain of thepresent control equipment is mounted.,`

Fig. 5 is an enlarged sectional view taken substantially along the line5-5 ofrFig. 2; and l Fig. 6 is a sectional view taken substantiallyalong the lined-6 of Fig. 5. l f i Referring now to the drawings indetail, in Fig. l there is illustrated a pair of diesel locomotive unitsoperatively connected to a train of passenger cars.Y The leading andtrailing diesel units 10Vand 11 respectively each include in addition toitsdiesel power plant, a steam generator 12 of the coiled water `tubetype such as has been illustrated in moredetail'in Fig. 3, and eachAgenerator 12 is operatively Vconnected-to a steam separator 13 hav,-ing a blowdown valve 14 and with which valves thecontrol mechanism ofthe present invention is operatively associated. As shown in Figs. 1 and4, certain portions of 4this control mechanism are operatively mountedon a control panel 15 suitably located in the cab ofthe diesel'.

ploye'd for tiring the generator. The ignition and burner structure isdesignated collectively at Z5 andthe 4outlet delivery valvesY 26 fromthe generator are shown as being connected by means of a conduit 27 to aregion near the upper end of the steam separator 13. The steam separatoris also of conventional design and is in the form of an elongated closedcylinder or tank 28 at the top of which there is mounted the usuallead-off valve 30 by means of which steam that has been separated fromits mineral constituents is sentthrough a pipe line to the heatexchangers or other devices (not shown) associated with the passengercar heating system. The lower end of the steam separator cylinder 28 isprovided with a central threaded opening 31 (Fig. 2) in which there isthreadedly received the tail piece 32 of the blowdown valve assembly 14.

The valve assembly 14 further includes a valve body 33 having an inletpassage34 in communication with a passage 35 in the tail piece 32 andconnected to the latter by a union ring 36. The valve body also has anoutlet passage 37 for sludge in communication with a nipple 38 which .isheld in position by a union ring 39. The tail piece 31 is provided witha valve seat 40 which cooperates with a valve element 41 carried at theupper end of a valve stem 42 which passes through a gland 43 and thestem 42 is spring pressed as at 44 to normally maintain the valveelement 41 seated on the tail piece seat 40.

As shown best in Figs. and 6, the valve element 41 is adapted to belifted from its seat 40 by depression of a foot pedal 45 pivoted as at46 on a rocker arm o1' lever 47 which in turn is pivoted as at 48 to anangular bracket 49 (Fig. 5) secured by studs 50 to the valve body 33. Apair of springs 51' serve to maintain the pedal 45 in its elevatedposition. The lever 47 has one end thereof disposed below and inengagement with the lower projecting end of the valve stem 42 and thusit will be seen that upon depression of the foot pedal 45 and consequentclockwise movement of the lever 47 as viewed in Fig. 6, the valve stem42 will be moved upwardly to lift the valve element 41 from its seat toe'ect the blowdown operation. 4In order that the operator may effect aprolonged blowdown operation without having to maintain foot pressure onthe pedal 45, a locking pin 52 extends upwardly from the body of thepedal and is designed for locking engagement with an abutment 53 formedon the bracket 49. By forward tilting of the pedal 45 after depressionthereof, the operator may align the end of the locking pin 52 with theabutment 53 (Fig. 5) to hold the valve 41 open. Release of the lockingpin may be effected by a reverse operation of the pedal 45.

The blowdown valve 14 per se when operated by a foot pedal 45 isconventional structure. The novelty of the present invention residesrather in the novel construction, combination and arrangement of partsabout to be described in detail whereby the blowdown operations may beautomatically performed at spaced intervals. Referring now to Fig. 2, anair cylinder assembly 60 is provided for each of the blowdown valves 14and is adapted to be secured to one flange of the angular bracket 49 bymounting screws 51. Each air cylinder includes a caslng 62 providing acylinder 63 therein in which there is slidable a piston 64 carried on aplunger 65 which projects downwardly from the casing and carries at itslower exposed end an adjusting stud 66 by means of which the electivestroke of the plunger may be varied within small limits. The stud 66 isdesigned for engagement with one end of a rocker arm 67 which is pivotedas at 68 to one arm 69 of the angle bracket 49 secured to valve 14. Theother end of the rocker arm 67 'carries an adjusting stud and lock nutassembly 70 which underlies the operative end of the lever 47 associatedwith the foot pedal 45 and which is designed for engagement therewith.

The cylinder 63 is bled to atmosphere as at 71 below the piston 64 andabove the-piston it is connected through :a conduit 7219 ,the Outletport I3 of a solenoid actuated valve assembly 74 operable uponenergization thereof to admit air under pressure to the cylinder 63through the conduit 72 to drive the piston 64 downwardly in the cylinder63 and thus cause counter-clockwise movement of the rocker arm 67 toelevate the valve stem 42 and lift the valve element 41 from its seat toeffect a blowdown operation.

The valve assembly 74 includes a casing 75 provided with an air inletport 76 and a bleeder port 77, the port 76 being connected through aconduit 78 to a suitable source of air under pressure (not shown). Theports 76 and 77 communicate through a common passage 80 with the outletport 73 and a pair of internal valve seats 81 and 82 at the ends of thepassage 80 cooperate with a dual valve and stem element 83 toselectively maintain the valve seats 81 and 82 open or closed in amanner that will be described presently. The valve element 83 isoperatively connected to the movable core S4 of a solenoid assemblyhaving a winding 85 operable upon energization thereof to move the valveelement 83 downwardly within the casing 75 to establish communicationbetween the air conduit 78 and conduit 72 through the ports 76 and 73 toeffect the blowdown operation as previously described. Upondeenergization of the winding 85 the valve element 83 is restored to itsnormal position under the influence of a spring 86 to establishcommunication between the ports 73 and 77 and bleed the cylinder 63 toatmosphere above the piston 64 and thus terminate the blowdownoperation.

The electrical control instrumentalities whereby the magnet winding 85of each solenoid valve 74 employed in any particular installation may beperiodically energized include a timer mechanism 90, schematically shownin Fig. 2 and which is conveniently mounted on the control panel 15(Figs. 1 and 4). This timer mechanism 90 operates to control the openingand closing movements of two cam operated switches 91 and 92 and isarranged in series in the electrical circuit for the solenoid valvewinding 85. A push button 93 permits manual blowdown operations at anydesired time irrespective to the positions of the cam operated switches91 and 92.

It has been found that in normal train operation it is desirable toeffect blowdown operations for a fixed time period at predeterminedintervals of time. The particular time period of the blowdown or theintervals bc tween such operations may vary, depending upon the quantityof sludge forming minerals contained in the Water in the region throughwhich the train is operated. Where pedal operated separator blowdownsare concerned it has been the practice of the trainman to appear at eachblowdown station periodically and depress the foot pedal 45, so as toopen the blowdown valve 41 for such period as the trainman deemed properto clear the sludge from the separator. Before entering a station andimmediately after leaving the same, it has been the custom to eect alonger blowdown impulse, utilizing the lock pin 52 and abutment 53 aspreviously described. The timer mechanism 90 of the present invention isdesigned to simulate these desired blowdown impulses with rhythmicaccuracy and in an unfailing manner but with an accelerated frequencywhich is impractical where manual operations are concerned.

Accordingly, as shown in Fig. 2, the cam switch 92 is adapted to beclosed by the timer mechanism at predetermined intervals, for example veminutes, and to remain closed for a shorter period, for example secondsduring each ve minute interval. During said tive minute period the camswitch 91 is closed a number of times, for example once each twentyseconds, and remains closed for at least one second. Consequently anenergizing circuit to the solenoid 85 of the air valve structure 74 iscompleted once during the time that the cam switch 92 is closed.

To effect the above described blowdown operations, closure @fthe masterswitch S will establish a circuit through the timer motor M, the circuitextending from a suitable source of current B, which may be a battery,through lead 94, switch S, leads 95, 96, motor M, and leads 97, 98, backto the source. Energization of the motor M serves to drive a timer cam99 through a iirst gear reduction train 100 and the cam 99 is formedwith a peripheral notch 101 which cooperates with a cam follower 102 topermit periodic closing movements of the cam switch 91 for the durationof one second duringv each twenty second interval of time. The timer cam99 is connected to a second timer cam 103 through a second gearreduction train 104.A The cam 103 is formedV with a peripheral notch 105which cooperates with a cam follower 106 to permit periodic closing ofthe cam switch 92 for the duration of twenty seconds during each iiveminute interval.

After initial closure of the switch S the system will continue tooperate indefinitely and the cam switch 91 will become closed for thebrief interval of one second at the end of each twenty second interval.Such closure of the cam switch 91 will be ineffective to energize themagnet winding 85 until such time as the cam switch 92 becomes closed atthe end of each five minute interval. At such times as both switches 91and 92 are closed a circuit will exist extending from the source Bthrough lead 94, switch S, leads 95, switch 91, lead 107, switch 92 andleads 108, 109, magnet Winding 85, and leads 110 and 98 to the source.Energization of the winding 85 will, of course, etect the blowdownoperation for the duration of such energization, as previouslydescribed.

From the above description it will be seen that the timer cam 103 servesto establish a twenty second period of time at the end of each tiveminute interval during which the switch 92 becomes and remains closed sothat during this period the separator 28 is potentially capable ofblowdown operation subject to the intermittent opening and closing ofthe switch 91 under the control of the timer cam 99. During theremainder of the iive minute interval, the switch 92 is open, and theperiodic intermittent closure of the switch 91 is without elect.

If kat any time it isdesired to effect manual blowdown of the separator13, the push button contacts 111 may be manually closed and such closurethereof will establish a circuit through the solenoid valve winding 85extending from the source through the contacts 111, leads 112, 109,winding 85 and leads 110 and 98 to the source. It is to be noted thatthis circuit is capable of being established at any time whether theswitch S is open or closed. The push button contacts 111 are designed topermit manual blowdown of the separator immediately prior to entry ofthe locomotive into a station. After such blowdown operation, theoperator should open the master switch S and leave the same open untilafter the locomotive has left the yard or station to disable the auto- Aterminal block 113 is mounted on the panel 15y and makes provisionwhereby the solenoid valves 74 of the variousseparators of the trainassembly may be connected in electrical parallel for simultaneousoperation by the timer control mechanism 90.

We claim:

A blowdown assembly for a steam separator having a normally closedblowdown valve including a casing and a stem projecting from saidcasing, means selectively operable for opening said valve includingamanually operable lever having an end portion engaging said projectingend of the valve stem which lever is movable individually in a directionto open said valve, a bracket secured to the casing for supporting saidmanually operable lever and provided with a stop surface thereon, a

second lever intermediately pivoted on said bracket and.

positioned to effectively bear at'one end against the valve stemengaging end of said manually operable'lever, a pressure fluid motormounted on said bracket for operatively engaging the other end of saidsecond lever to rock it and the said manually operable lever in adirection to open said valve, and means carried by said manuallyoperable lever for releasably engaging said stop surface on the bracketto lock the said manually operable lever in its valve operatingposition.

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